Gypsy Moth Infestation: If You Thought Last Year Was Bad, They're Coming Back

MASSACHUSETTS, MA — Experts say we're in for another doozy, so you may want to check your trees, and buy one of those netted hats. The area last year endured a gypsy moth infestation that hadn't been seen since we were fixated on conquering the Rubik's Cube. It broke records.

The moths sucker punched Massachusetts, particularly the South Shore, during the heart of last summer, the little buggers flocking in hordes onto floodlit doorways.

“I would say almost surely this is the largest outbreak we’ve seen since 1981," Joe Elkinton, a professor of environmental conservation at UMass Amherst, said in a school publication. "This is unprecedented. It’s been 35 years. Defoliation caused by gypsy moth Lymantria dispa has occurred over this summer, in many parts of Massachusetts and the rest of New England.”

Patch learned that a guy named E. Leopold Trouvelot introduced the moth when he tried to make a go of a silk industry in the mid-1880s.

State environmental officials on Thursday announced a prediction of another year of "defoliation from the gypsy moth." Following widespread defoliation by the invasive gypsy moth in 2016, state environmental officials are predicting another season of "higher than usual" caterpillar feeding in 2017.

Homeowners are encouraged to check out the trees on their property to identify egg masses due to the absence of leaves, and to begin the scheduling of the treatment process with a certified arborist or licensed pesticide applicator. Foresters performed egg mass surveys throughout the state, and confirm the likelihood of higher than normal gypsy moth caterpillars this spring.

According to the announcement, gypsy moth populations in Massachusetts have generally experienced cyclical patterns, but have been controlled by natural factors, including weather, natural and introduced enemies, and the resilience of Massachusetts forests to withstand defoliation. Recent drought conditions have limited the effectiveness of a soil borne fungus, Entomophaga maimaiga, which has helped keep gypsy moth populations in check since the last large outbreak during the 1980s. Trees can overcome a single defoliation event, but many years of severe insect feeding, or the addition of other stressors such as drought, can lead to long-term tree damage or tree mortality.

“The Department of Conservation and Recreation remains steadfast to combating invasive species like the gypsy moth to ensure the Commonwealth’s natural resources are protected for all to enjoy,”said DCR Commissioner Leo Roy in a statement. “The agency will continue to monitor the situation; however, by sounding the alarm early, we hope to provide the public with ample opportunity to treat their own trees before it is too late.”

Forest health specialists recommend targeted treatments in areas that suffered repeated defoliation. Trees should be checked beginning in the first week of May for signs that the egg masses have hatched; look for tiny, black, hairy caterpillars, only 3-5mm long, traveling from the pink egg masses in search of food, or congregating on the undersides of the leaves of oaks and other trees.

Find out more information here.

Photo via Wikimedia Commons